208 Mr. J. W. Slater on the 



hand, the caterpillar of the death's-head is strikingly 

 coloured, and of its food-plant, the potato, we may surely 

 say that all parts above the soil are poisonous. 



It will be at once objected that in the food of the mag- 

 pie- or currant-moth, conspicuous and protected as its 

 larva is well known to be, there is nothing poisonous. 

 This is perfectly true, but in the currant-bush there are, 

 so to speak, the raw materials for a most offensive odour. 

 If the shoots of a currant-bush are dried in a slow 

 oven, the smell produced strongly resembles that of 

 the urine of cats. It may not be generally known that 

 the juices of the magpie-caterpillar are decidedly irritat- 

 ing to the skin. I have been assured by Lancashire 

 gooseberry fanciers, who often pick the caterpillars off 

 their choice bushes by hand, that after this operation their 

 fingers were often red and painful. 



I have not been able to ascertain anything definite 

 concerning the caterpillars of the Heliconias, nor yet con- 

 cerning the plants upon which they feed. Both Mr. Bates 

 and Mr. Belt notice the unpleasant and enduring smell of 

 the insect when mature. Mr. Bates describes the cater- 

 pillar of a Sphinx which he found on the leaves of a tree 

 on the open llanos of South America. " It was about four 

 inches in length, transversely banded with black and 

 yellow, and with its head, legs and tail of a bright red. 

 It caught the eye at the distance of many yards." I am 

 indebted to him for the information that to the best of his 

 remembrance the tree abounds in prussic acid. 



Mention was made, in an interesting paper lately read 

 before this Society, of the recent spread of Danais 

 Archippus. The poisonous character of the Asclepiads, 

 upon which this insect and its allies feed, is well known, 

 and the caterpillars are decidedly conspicuous. That of 

 D. Archippus is described as whitish with yellow lines 

 and black transverse bands. The caterpillar of Danais 

 Chrysippus is of a purplish-white, ringed with black and 

 yellow. 



The caterpillar of Thais Polyxena is yellow, spotted 

 with black, and with five rows of reddish-orange spines. 

 It feeds upon some species of Aristolochia, a tribe of 

 plants known for its violently purgative and vermifuge 

 properties. 



It would be important to ascertain by direct experiment 

 in how far caterpillars feeding upon poisonous plants are 



